Fans were startled to learn that Harry Styles and Olivia Wilde were suddenly dating.

After all, they first met on the set of their film "Don't Worry, Darling" a few months after their affair began, and a few weeks into filming, Wilde breaks up with her long-term lover, Jason Sudeikis.

But in just a few weeks, Styles and Wilde will walk the red carpet at the Venice Film Festival for the global premiere of the latter's film.

Florence Pugh will be joining them.

According to Page Six, the 26-year-old British actress has a falling out with the 38-year-old director after hooking up with the "Watermelon Sugar" hitmaker.

"I can tell you for a certainty that Flo seeing Olivia and Harry all over one other on set did not go over well because Olivia was still with Jason when she initially hooked up with Harry," a source told the magazine.

Wilde and Sudeikis, who were engaged in 2012 and have two children, Otis, eight, and Daisy, five, announced their separation in November 2020.

Insiders said at the time that the "Book Smart" director's connection with the former One Direction star was the major reason for the separation, with one source telling the magazine that the romance had been going on for a month. Sudeikis was "distraught" as a result.

"Jason and the kids visited Olivia on set a few times in the beginning, so I think this made folks feel a little uncomfortable," a source stated this week.

READ ALSO: Brad Pitt Dating 2022: Is Angelina Jolie's Ex Ready To Fall In Love Again Amid Legal Troubles?

Internet sleuths suspect a rumored feud, noting that, in an industry where celebrities are obsessed with Instagram, Pugh omitted to "like" a post last week in which Wilde shared the whole official trailer for their film.

Wilde even captioned a photo of Pugh, "Watching this woman work was such an f--- joy!!!" "I can't wait to show you more," she said, tagging the actress and the film's official Instagram page.

Pugh, per Page Six, stood out by her silence. She did, however, provide a teaser trailer for another movie she's working on called "Oppenheimer."

Now, Florence Pugh's rejection and quiet on everything Wilde-related has sparked a heated argument on social media, with one user writing, "I think it's so amusing how Florence pugh had mentioned NOTHING about don't worry, darling, and Olivia Wilde keeps trying to hype her up."

"I need to know what Olivia Wilde did to my daughter Florence Pugh on the set of DWD since my girl has been SILENT on movie updates," another user said.

According to an insider, Pugh was originally slated to write about "Oppenheimer" that day for "some specific purpose," but it had "nothing to do with a reaction to Olivia."

READ MORE: 'The Wendy Williams Show' Producers Contributed To Host's Downfall? The Truth!